Pyridine derivatives having antidepressant activity

ABSTRACT

AND THEIR THERAPEUTICALLY ACCEPTABLE ACID ADDITION SALTS, WHEREIN R1 is a member selected from the group consisting of hydrogen and methyl, R2 is a member selected from the group consisting of hydrogen, alkali metal, alkyl containing from 1 to 3 carbon atoms, alkyl substituted with hydroxyl and containing from 1 to 3 carbon atoms, benzyl and benzyl substituted with halogen, and n is 0 to 1. The new compounds of formula I are valuable anti-depressant agents.   Pyridine derivatives of the formula

United States Patent 1191 Korosi et al.

1451 Feb. 11, 1975 PYRIDINE DERIVATIVES HAVING ANTIDEPRESSANT ACTIVITY [75] Inventors: Jeno Korosi; Gabriella Szabo Nee Czibula; Lay Nee Konya, Aranka; Lujza Erdelyi Nee Petocz; Bolya Balla Nee Kosoczky; Eniko Kiszelly, all of Budapest, Hungary [73] Assignee: EGYT Gyogyszervegyeszeti Gyar,

Budapest, Hungary 22 Filed: Nov. 1,1972

211 App]. No.2 302,891

Related US. Application Data [63] Continuation-impart of Ser. No. 236,953, March 22, I972, abandoned.

I52] U.S. (fl... 260/268 C, 260/295 R, 260/295 AM,

OTHER PUBLICATIONS Ueda et aL, Chemical Abstracts, Vol. 59, p. l603d, (i963).

Symchowicz et al., Chemical Abstracts, Vol. 70, 80846p, (1969).

Primary Examiner-Donald G. Daus Assistant Examiner--J0se Tovar Attorney, Agent, or Firm-Young and Thompson [57] ABSTRACT Pyridine derivatives of the formula and their therapeutically acceptable acid addition salts, wherein R is a member selected from the group consisting of hydrogen and methyl, R is a member selected from the group consisting of hydrogen, alkali metal, alkyl containing from I to 3 carbon atoms, alkyl substituted with hydroxyl and containing from 1 to 3 carbon atoms, benzyl and benzyl substituted with halogen, and n is 0 to l.

The new compounds of formula I are valuable anti-depressant agents.

3 Claims, N0 Drawings PYRIDNE DERIVATIVES HAVING ANTIDEPRESSANT ACTIVITY This application is a continuation-in-part of our copending application Ser. No. 236,953, filed Mar. 22, 1972 now abandoned.

This invention relates to new pyridine derivatives and the therapeutically acceptable acid addition salts thereof.

The new compounds according to the invention have.

the following formula wherein R and n have the same meanings as above and R stands for a halogen atom, a hydroxyl group, an amino group or a straight or branched-chain alkoxy group containing from I to 4 carbon atoms, or a therapeutically acceptable acid addition salt thereof with a piperazine derivative having the formula HN N R (III) wherein R has the same meaning as above, or a therapeutically acceptable acid addition salt thereof, and if desired, the obtained compound of formula I containing a hydrogen atom as the substituent R is transformed to a compound of formula I containing an alkali metal atom as the substituent R This compound can be transformed, if desired, by reacting with alkylating or aralkylating agents to a compound of formula I containing an alkyl group having from 1 to 3 carbon atoms or an alkyl group containing from 1 to 3 carbon atoms and substituted with a hydroxyl group, a benzyl group or a benzyl group substituted with a halogen atom as substituent R If the obtained compound of formula I is a free base, it can be converted into a therapeutically acceptable acid addition salt by reacting it with a therapeutically acceptable acid or, if desired, the acid addition salt can be transformed in a known way into the free base by reacting it with a strong base, or the acid addition salt can be transformed into another acid addition salt by reacting it with another therapeutically acceptable acid.

The free bases having the formula I can be purified before forming the salts preferably by recrystallization or vacuum distillation but the crude bases of formula I can also be used for the salt formation.

If compounds of the formula II, wherein R stands for a hydroxyl, amino or alkoxy group containing from 1 to 4 carbon atoms, are used as starting material, these compounds are preferably reacted at a temperature of l40-250C. with the compounds of formula III. The reaction can be carried out in the absence of any solvent or in the presence of a solvent of higher boiling point, such as ethyleneglycol, formamide, dimethylformamide, benzylalcohol, or diphyl, which is the eutectic mixture of diphenyl and diphenyl ether, e.g. Dowtherm A."

If during the preparation of the compounds of formula I one starts from compounds of formula 11 containing a halogen atom as the R substituent, then the reaction is preferably carried out at 0-l00C., in the absence of any solvent or in a neutral solvent, such as ether, dioxane, benzene or carbon tetrachloride.

The starting materials having the formulas II and 111 are known compounds (US. Pat. No. 2,415,785; J. Chem. Soc. 1927, 47; 1959, 3634; CA. 45, 5954 (1951); 47, 617 (1953)).

The new compounds according to the invention have proved to be antidepressant agents of considerable therapeutical value. Compounds of similar structure are described in the technical literature at a single site (Pharmacia (Bucharest) 10, 35, 81 (1962); CA. 58, 522, 11359 1963)). The known compounds have been prepared by reacting N-methyl-piperazine and nicotinic or isonicotinic acid chloride, and their cardiovascular effect has been investigated. According to our own tests these known compounds have no appreciable antidepressant effect.

The new compounds of formula 1 show according to pharmacological tests a strong tetrabenazineand reserpineantagonizing effect.

The effects and toxicity data of the dihydrochlorides of the compounds having the formula I are summarized in Table 1. The corresponding data of the known 5- (gamma-dimethylaminopropylidene)-dibenz(a,d)1,4- cycloheptadiene (Amitryptilin) having antidepressant effect are given for comparison. The tests have been carried out on mice. The compounds have been given orally.

The therapeutical index (LD /ED of a part of the compounds having the formula I is more favorable and is in some cases by orders of magnitude higher than 3 4 that ofthe compound used for comparison. Moreover, illustration only and are not to be construed as limiting the compounds of formula l have catalepsy-inhibiting, the claimed scope of the invention.

local anaesthetic and/or sedative effect as well.

Further new pyridine compounds were prepared ac- EXAMPLE 1 cording to the method of the invention. For the sake of 5 Preparation of N-picolinoyl-piperazine completeness, their pharmacological data are shown in A mixture of 27.4 g. (0.2 mole) of picolinic acid Table 2. methylester (or of 30.2 g. (0.2 mole) of picolinic acid Table 2 ethylester or of 35.8 g. (0.2 mole) of picolinic acid nbutylester) and of 51.6 g. (0.6 mole) of anhydrous pi- EDw g g perazine is kept for 25 hours at l35l45C. whereafter Tetrabena. Reserpine. the excess of piperazine is distilled off from an oil bath LD gg z of 240C. The residue is fractionally distilled under a Compound ru /g e%fect g effe ct pressure of 0.1 mm Hg. In this way 2l-23 g. (55-60 percent) of N-picolinoyl-piperazine are obtained with y y a melting point of l52-l55C. (0.l mm Hg.) The i 'erazine I000 l2.5 20.5 {iifisonicofinoyi product crystallizes while standing; m.p.: 7273C. piperazine 3000 47.5 140 N-isonicotinoyl-N benzyl-piperazine 1200 3 l l 8 O0 2 2 fils'ifirfilofiiffi'ifgf chlorobenzyl)-piperazine 1225 =200 1 l5 Calculated, N 21.97 N-nicotinoyl-N'-(p- Found, N 2l.65 chlorobenzyl )-piperazine 680 200 100 N-(pyridyl-4-acetyl)- N-benzyl-pi erazine 600 1.1 27 F n- The white crystalline N-picolmoyl-piperazme dihyd- (P- y rochloride melts, after recrystallizing from methanol, at plperazme 210 50 50 o N (pyr'idyl 3 acryloyl) 210 C. with decomposition. N'-methyl-piperazine 2200 35 120 N-(pyridyl-4-acetyl)- N-methyl-piperazine 400 43 100 N-(pyridyl-3-acetyl)- N'-methyl-piperazine 520 52 60 A data (M46417) N-(pyridyLB-acetyU- Calculated, %2 N 15.9] Cl 26.84 N'-benzyl-piperazine 760 47 44 Found, N 15-95 Cl 2 -3 N-(pyridyl-3-propionyl)- N'-methyl-piperazine 1500 130 r20 EXAMPLE 2 Preparation of N-picolinoyl-piperazine A mixture of 8.6 g. (0.1 mole) of anhydrous piperar the n can 53 the m P m zinc and of 12.2 g. 0.1 mole) of picolinic acid amide ceutlcal compositions comprising as active ingredient is refluxed for 20 hours on an Oil b of 5 to at least one p m of fm m admixture 160C, w'hereafter the mixture is fractionally distilled suitable pharmaceutical exciplents and carriers. under a pressure f (H mm Hg In this way 21 5 These pharmaceutical compositions can be solid, e.g. I percent) f N picolinoyl piperazine are Obtained The tablets. pills, capsules. Suppositories, coated pills, or product is identical with the product of Example 1. liquids, such as solutions, emulsions or injectable preparations. The compositions can be suitable for oral, EXAMPLE 3 rectal Peremeral administration Preparation of N-(6-methyl-picolinoyl)-N-methyl The carriers can be conventional organic or inorpi i ganic substances, such as starch, magnesium stearate, A mixture f33 0 (0,2 l f 6- h 1- i 1i i talc,stfiarifler P y y glyeols, magnesium Carbon acid ethyl ester (or 38.6 g. (0.2 mole) of 6-methylate, Water, e c. picolinic acid n-butylester) and of 20.0 g. (0.2 mole) of The Pharmaceutical compositions can contain addi' N-methylpiperazine is refluxed for 20 hours on an oil fi such asemulsifying, stabilizinaflavcring.disintebath of 17o-200c., whereafter the mixture is fracgrating and Wetting agents, In addition to the tionally distilled off under a pressure of 0.4 mm Hg.

pounds of formula 1 they can comprise further thera- 195-22 (45 5() percent) f li h ll il N 6 Peutieany active Compounds as wellmethyl-picolinoyl)-N'-methyl piperazine are obtained The pharmaceutical compositions embodying the inas the main product vention can be prepared by usual methods known per se in the pharmaceutical industry, by admixing the active ingredient with suitable solid or liquid organic or inorganic pharmaceutical carriers and/or excipients 6O Whdwlg) and,,if desired, with other therapeutically active comgjffi N :18 pounds.

The dose of the compounds according to the invenv tion for adults can vary between about 20 mg. to about 6 After recrystallization from ethanol, the white crys- 450 mg. per day. talline N-.(6-methyl-picolinoyl)-N'-methyl-piperazine The invention is further illustrated by the aid of the dihydrochloride melts at 247-248C. with decomposifollowing Examples which are given for the purpose of tion.

Preparation of N-picolinoyl-benzyl-piperazine A mixture of l5.95 g. (0.1 mole) of picolinic acid hydrochloride and of 17.6 g. (0.1 mole) of N-benzylpiperazine it kept in an apparatus for hours at l60-l70C. The obtained N-picolinoyl-N-benzylpiperazine monohydrochloride is dissolved in 200 ml.

N-picolinoyl-piperazine (prepared according to the method described in Example 1) in 150 ml. of absolute dioxane 2.3 g. of sodium metal powder are added during one hour in portions while stirring. The mixture is left to stand at room temperature for one day. During one hour 0.] mole of benzyl chloride is dropped into the obtained N-picolinoyl-piperazinesodium while external cooling with water, whereafter the mixture is heated to boiling. The separated sodium chloride is til tered, the solvent is distilled off and the residue is fractionally distilled under vacuum. ln this way I82 g. (65 percent) of N-picolinoyl-Nbenzykpipcrazinc :u'c oi tained with a melting point of 2 l 8220C./0.l mm Hg. The product is identical with the product of Example of hot absolute ethanol, and the solution is acidified at 4. 50-70C. with absolute ethanol saturated with hydrochloric acid. The pH of the solution is controlled with EXAMPLES 6 to lo indicator paper. The mixture is kept for some hours in The compounds enumerated in Table 3 are prepared a refrigerator, whereafter the separated crystals are filin compliance with the process as described in the pretered, washed with 2X20 ml. of ethanol and dried. In vious Examples.

Table 3 M.p. of the According B.p. of dihydrochloride, C. No. of R R2 to Yield the base (recrystallizing Example Ex. No. mm Hg. solvent) 6 CH H I 55-60 137-139/005 l60-l62 (b) 7 H CH 3 130-133/0.1 202-204 d. (e) 8 H CH CH- 3 50-55 209-212/0.4 2l0-2l3 d. (c)

OH 9 CH3 Cl -l -Cl-l- 3 4550 l97l99/0.2 222-223 (c) OH 10 CH3 Cl l -C H 3 70-75 240242/0.8 200-202 (c) d. decomposition (b) recrystallization: the product is dissolved in methanol and then precipitated with acetone (c) recrystallized from 96% ethanol (e) recrystallized from absolute ethanol this way 20.3 g. (58 percent) N-picolinoyl-N'-benzylpiperazine dihydrochloride melting at 2l42l5C. with decomposition are obtained. After recrystallizing from absolute ethanol the point of decomposition rises to 2l6-217C.

Analysis data (M=354.29) Calculated, N 11.86 Cl 20.01 Found, N ll.91 Cl 19.70

The N-picolinoyl-N-benzyl-piperazine maleate (C H N O.C H O melts at l69-l70C. while the N- picolinoyl-N-benzyl-piperazine fumarate (C17H19N3O.C4H4O4) melts at 165 EXAMPLE 5 Preparation of N-picolinoyl-N'-benZyl-piperazine To a hot solution of 19.] g. (0.1 mole) of What we claim is: l. A pyridine derivative selected from the group con- 5 sisting of a compound of the formula 

1. A PYRIDINE DERIVATIVE SELECTED FROM THE GROUP CONSISTING OF A COMPOUND OF THE FORMULA
 2. A pyridine derivative as claimed in claim 1, in which R1 is hydrogen.
 3. N-picolinoyl-benzyl-piperazine. 